FACTDOUBLE

Calculates the double factorial[1] of a number.

Syntax:

FACTDOUBLE( number )

Returns the double factorial of a number (commonly shortened to n!!).

number must be an integer greater than or equal to minus one.

Revisions:

This function was added in 2.00.

  1. Weisstein, Eric W. "Double Factorial." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/DoubleFactorial.html